The invention generally relates to methods, apparatuses, systems, network elements and programs e.g. for power control or power setting for example for mobile communication or connection etc.
One or more embodiments of the invention relate to power control or setting for communication such as wireless communication like mobile wireless communications, such as e.g. third generation partnership project, 3GPP, long-term evolution (LTE & LTE-A). One or more embodiments may relate more specifically to one or more of network optimization, automated configuration and interference reduction in case of e.g. wide area cell with femto-cell co-channel deployment.
Femto-cells can be small or very small base stations. In fact femto cells may be so small that they can e.g. be placed in a customer's residence. In 3GPP standardization femto-cells are called “Home Node B” (HNB) for wideband code division multiple access, WCDMA, and “Home eNode B” (HeNB) for LTE. Such femto-cells are also termed femto base stations, home base stations or home Node Bs or evolved home Node Bs in this specification. Likewise, wide area cells or base stations are also termed macro cells, macro base stations, or macro or wide area Node Bs in this specification.
Implementations of femto-cells provide benefits for operators, users, and/or customers. Some benefits are provided by e.g. off-loading macro radio network traffic to femto nodes; improving coverage and/or capacity locally in a cost-effective manner; and/or implementing home-zone services to increase service offering and utilization.
Further, to utilize the spectrum efficiently, co-channel deployment of femto base stations such as HNBs or LTE HeNBs may be considered, providing an important use case in 3GPP standardization.
This means that HNBs may use the same spectrum as the wide area Node B, NBs, rather than an independent second spectrum area (say two blocks of 20 MHz each). However, sacrificing one carrier for HNBs takes away capacity from the wide area network, WAN, which may be undesirable e.g. in case operators do not have too much spectrum available.
Like wide area or macro base stations, small area base stations or femto base stations such as HNBs or HeNBs, may connect terminals such as user equipments like LTE user equipments to an operator's network by a physical broadband connection which may for example be a digital subscriber line, DSL, connection. Further they may operate in residential or e.g. small office environment and users may move between indoor and outdoor. Therefore a handover mechanism between the macro network and the femto cell such as HNB or HeNB may be provided. Regarding service capabilities HNBs, or HeNBs should be able to handle data and simultaneous voice calls.
Besides the issues mentioned above, another characteristic of femto base stations such as HeNBs is their ability to control access. Common access types are open and closed access. In an open subscriber group (OSG) scenario, any terminal/subscriber can be served by the base station such as HeNB. In a closed subscriber group (CSG) scenario, the base station such as HeNB serves only a limited number of subscribers that are allowed to access a given base station or HeNB.
In this context, interference from the femto cell such as HNBs or HeNBs to the wide area network is an issue. Initial operator deployments may use the same frequency for both the femto networks such as HeNB and the macro networks. With closed subscriber groups, access of a visiting user equipment not belonging to the closed group, to the femto base station or cell such as HeNBs is prevented, and wide area dead zones may be caused by the downlink interference from the HeNB which makes it also impossible to the visiting user equipment to access the wide area network.